1. Field of the Invention
This invention relates to a coolant cooled type semiconductor device.
2. Description of the Related Arts
To improve cooling characteristics of semiconductor modules that contain semiconductor chips having terminals, it has been proposed that water cooling type cooling members are made in contact with semiconductor modules so as to cool these semiconductor modules. Also, Japanese Laid-open Patent Application No. Hei-6-291223 has proposed a double-sided heat-radiating type semiconductor module in which heat is radiated from both surfaces of this semiconductor module.
However, in the above-described conventional water-cooling type semiconductor modules, a cooling member must be joined to the semiconductor modules, while maintaining superior heat transfer characteristics. To realize such superior heat transfer characteristics, there is the best way such that an electrode (also having heat transfer function) that is exposed from the main surfaces of the semiconductor modules is joined to the cooling member by a soldering material.
If the cooling member is a cooling unit through which water or coolant passes, the cooling unit may be connected to either a refrigerating cycle apparatus or a cooling water circulating apparatus. Therefore, the above-explained electrode member of the semiconductor module and the cooling member is set to a predetermined potential (normally, ground potential) equal to that of the refrigerating cycle apparatus, or the cooling water circulating apparatus.
However, when such an electrically insulating spacer is employed, since the electrode member of the semiconductor module cannot be joined to the cooling member, the electrode member of the semiconductor module and also the cooling member must be strongly pressed against the electrically insulating spacer under such a condition that uniform pinching pressure is given to the respective face portions in order to reduce the thermal resistance between the electrode member of the semiconductor module and the cooling member.
The above-described construction in which both the semiconductor module and the cooling member are strongly pressed against the insulating spacer under uniform pinching pressure would induce the complex entire structure. Also, the pinching force cannot be controlled easily. In other words, when the pinching force is low, the thermal resistance between the semiconductor module and the cooling member is increased, so that the cooling capability is lowered. To the contrary, when the pinching force is excessively high, the semiconductor chips built in the semiconductor module are broken.
Also, in order to cool double-sided of a large number of these semiconductor chips, or double-sided cooling type semiconductor card modules, a large number of the above-explained cooling members are branched, resulting in complex structures and increased manufacture cost. These increase the risk that fluids may be leaked due to an increased total number of joint places of the coolant distribution tubes.